As described in Holden, H. A. and Babinsky, H. (2003) Shock/boundary layer interaction control using 3D devices In: 41st Aerospace Sciences Meeting and
Exhibit, Jan. 6-9, 2003, Reno, Nev., USA, Paper no. AIAA 2003-447, as a transonic flow passes over a 3-D shock bump the supersonic local conditions induce a smeared shock foot with a lambda-like wave pattern.
The bumps described in Holden et al. are asymmetrical fore and aft, typically increasing in height and/or width to a maximum height and/or width to the rear of the centre of the shock bump. In other words, the bumps are asymmetrical about a plane which passes through a centre of the shock bump and is normal to the free stream direction. However, to date all evaluations of three-dimensional shock bumps have been restricted to laterally symmetric bump shapes, aligned with the free stream direction. In other words, conventional shock bumps are symmetrical about a plane which passes through a centre of the shock bump, is parallel with the free stream direction, and extends at a right angle to the surface of the aerofoil.
US 2006/0060720 uses a shock control protrusion to generate a shock extending away from the lower surface of a wing.